Wafer for cleaning semiconductor device probe

ABSTRACT

A system and method for cleaning probe pins on a probe card used in testing a semiconductor device during fabrication thereof. A ceramic cleaning wafer is utilized to clean the probe pins without having to remove the probe card from a production line. The same apparatus used to test production wafers also handles the cleaning wafer during a probe cleaning cycle. During operation of the cleaning cycle, the cleaning wafer is placed in a manual load tray, which inserts the cleaning wafer into a prober machine. The cleaning wafer is transported by a robotic trolley to a prealign stage area where the cleaning wafer is aligned and centered. The cleaning wafer is then placed on a support device. The support device and cleaning wafer are positioned under a pneumatic sensor and profiled to determine wafer planarity. The support device and cleaning wafer are then positioned underneath the probe pins on the probe card to be cleaned. Thereafter, the z-axis distance between the probe pins and the surface of the cleaning wafer is decreased such that the probe pins contact the cleaning wafer, thereby removing debris from the probe pins. The cleaning wafer is then removed from the support device when cleaning of the probe pins has been completed.

RELATED APPLICATIONS

This application is a divisional application of U.S. patent applicationSer. No. 09/027,018, filed on Feb. 20, 1998, now U.S. Pat. No.6,019,663, which is incorporated herein by reference.

BACKGROUND OF THE INVENTION

1. The Field of the Invention

The present invention relates generally to semiconductor device testingduring fabrication. More particularly, the present invention relates toa system and method that employs a cleaning wafer for in-line cleaningof probe pins on a probe card used in testing semiconductor devicesduring fabrication.

2. The Relevant Technology

During fabrication of semiconductor devices from silicon wafers, aprober machine is used to interface a semiconductor device to a testermachine while still in wafer form prior to cutting the wafer intoindividual chips. A typical prober machine includes a probe card havingan array of probe pins that contact bond pads on the semiconductordevice during testing. The bond pads on the semiconductor device aremade from metallic materials such as aluminum which can oxidize whenexposed to air. Also, organic material left over from certainfabrication processes can be disposed on the bond pads. When probe pintips repeatedly contact bond pads on a silicon wafer, metal oxides suchas aluminum oxides and other materials on the bond pads can build-up onthe probe pin tips, thereby interfering with the function of the probepins during testing operations. Thus, it becomes necessary toperiodically clean the probe pins on a probe card.

In conventional cleaning operations, a probe maintenance station isutilized in order to clean probe pins on a probe card used in testingfabricated semiconductor devices. This requires the removal of the probecard from the production line in order to clean the probe pins,resulting in a certain amount of production downtime. The productiondowntime includes the time to remove the probe card from the prober, andthe time to install and perform a complete new set up for a clean probecard. Also, additional time is spent in taking the dirty probe card to ahardware support facility, in cleaning/aligning, and documenting theprobe card, and in getting the cleaned probe card back to productionpersonnel.

As manufacturing techniques have improved, it has become possible toprobe more semiconductor dies in parallel at one time, requiringincreasingly wider probe card arrays. This has resulted in everincreasing difficulty and downtime in order to have the probe cardarrays taken off-line, to replace the probe card arrays, and then tobring the system back online, as well as additional time to clean theremoved probe card arrays and bring the arrays back into service. Whilevarious ceramic burnishing chucks have been used in the past to cleanprobe tips, such as separate chucks with a piece of ceramic thereon forthe probes to touch down on for cleaning, such conventional burnishingchucks are too small for the wider probe cards currently used.

Accordingly, there is a need for improved probe pin cleaning systems andmethods that overcome or avoid the above problems.

SUMMARY OF THE INVENTION

The present invention is directed to a system and method that employs acleaning wafer such as a ceramic wafer disc for in-line cleaning ofprobe pins on a probe device such as a probe card in a prober machineused in testing semiconductor devices during fabrication. The shape andthickness of the cleaning wafer is similar to a silicon productionwafer, allowing the cleaning wafer to be inserted in place of thesilicon production wafer in order to perform a cleaning cycle for theprobe pins without having to remove the probe card from a productionline. The cleaning wafer is used to make contact with the probe pin tipsand remove any buildup of oxides or other undesired substances that tendto accumulate on the so probe pin tips. The same apparatus used to testproduction wafers also handles the cleaning wafer during a probecleaning cycle.

During operation of the cleaning cycle, the cleaning wafer is placed ina manual load tray or auxiliary tray, which inserts the cleaning waferinto a prober machine. The cleaning wafer is transported by a robotictrolley to a prealign stage area where the cleaning wafer is aligned andcentered. The cleaning wafer is then placed on a support device. Thesupport device and cleaning wafer are positioned under a pneumaticsensor and profiled to determine wafer planarity. The support device andcleaning wafer are then positioned underneath the probe pins on theprobe card to be cleaned. Thereafter, the z-axis distance between theprobe pins and the surface of the cleaning wafer is decreased such thatthe probe pins contact the cleaning wafer. The probe pins can berepeatedly contacted with the cleaning wafer to remove unwanted debrisfrom the probe pins. The cleaning wafer is removed from the supportdevice and prober machine when cleaning of the probe pins has beencompleted.

The cleaning wafer preferably has a substantially circular shape andblocks transmission of nonionizing electromagnetic radiation energytherethrough such as infrared light energy. In one embodiment, thecleaning wafer has a first abrasive surface made of a ceramic materialcapable of removing unwanted debris from a probe tip, and a secondopposing surface having an opaque coating thereon capable of blockingtransmission of infrared light energy through the wafer. An outerperiphery between the first and second surfaces has a notch formedtherein to allow proper alignment of the cleaning wafer when loaded intothe prober machine.

The present invention allows probe pins on a probe card to beeffectively cleaned while still installed in a prober machine, therebyeliminating the need to remove the probe card, reinstall a clean probecard, and rerun a complete new set-up for the clean probe card. Thisresults in a reduction in production downtime.

Other aspects and features of the present invention will become morefully apparent from the following description and appended claims, ormay be learned by the practice of the invention as set forthhereinafter.

BRIEF DESCRIPTION OF THE DRAWINGS

In order to more fully understand the manner in which the above-recitedand other advantages and objects of the invention are obtained, a moreparticular description of the invention briefly described above will berendered by reference to specific embodiments thereof which areillustrated in the appended drawings. Understanding that these drawingsdepict only typical embodiments of the invention and are not thereforeto be considered limiting of its scope, the invention will be describedand explained with additional specificity and detail through the use ofthe accompanying drawings in which:

FIG. 1 is a schematic plan view of a prober system that can utilize thecleaning wafer according to the invention to clean probe pins on a probecard used in testing semiconductor devices during fabrication;

FIG. 2 is a side view of part of the prober system of FIG. 1, showingthe cleaning wafer in position to clean the probe pins on a probe card;

FIG. 3 is an enlarged sectional side view taken along line 3-3 of FIG.2, depicting in more detail the probe pins in position to be cleaned bythe cleaning wafer according to the invention;

FIG. 4A is a plan view of one embodiment of a cleaning wafer accordingto the present invention that can be utilized in the system of FIG. 1;and

FIG. 4B is a plan view of another embodiment of a cieaning waferaccording to the present invention that can be utilized in the system ofFIG. 1.

DETAILED DESCRIPTION OF THE INVENTION

The present invention is directed to a system and method that employs acleaning wafer such as a ceramic wafer disc for in-line cleaning ofprobe pins on a probe device such as a probe card in a production probermachine used in testing semiconductor devices during fabrication. Thus,the cleaning wafer of the invention is used to clean probe pins on aprobe card while still in a production setting. The shape and thicknessof the cleaning wafer is similar to a silicon production wafer. Thisallows the cleaning wafer to be inserted in place of a siliconproduction wafer in a prober machine in order to perform a cleaningcycle. The cleaning wafer is used to make contact with probe pin tipsand remove any buildup of oxides or other undesired substances that tendto accumulate on the probe pin tips. By making several touchdowns on theceramic wafer disc, the oxides or other debris can be cleaned from theprobe pin tips.

The cleaning wafer of the invention can be made of any abrasive materialthat has a suitable grain size for cleaning the probe pins. The roughsurface on the wafer acts as an abrasive to clean off the probe pintips. The cleaning wafer can be made from a variety of commerciallyavailable materials. Preferably, a ceramic material is used to make thecleaning wafer, including materials such as alumina, silicon nitride,silicon carbide, tungsten carbide, and mixtures thereof. One suitableceramic material is SupraSurf ADS-995 available from Coors CeramicsCompany, of Oakridge, Tenn. This ceramic material has a 5 microinchsurface finish, with an average grain size of up to 2.2 microns, and ismade primarily of alumina.

The cleaning wafer preferably has a circular shape in the form of a flatdisc. The cleaning wafer can be formed such that both surfaces of thewafer are abrasive. In one embodiment, the cleaning wafer of theinvention is sized to have a diameter of about 8 inches (about 200 mm)and a thickness of from about 10 mil to about 50 mil, and preferablyfrom about 20 mil to about 40 mil. The cleaning wafer preferably has aplanar surface that deviates less than about 6 microinches.

In order for the cleaning wafer of the invention to be properly loadedin a prober machine during production, it is necessary to preventradiant electromagnetic energy from traveling through the cleaningwafer. Thus, a ceramic cleaning wafer according to the invention ispreferably rendered opaque in order to block transmission of nonionizingradiant electromagnetic energy therethrough, particularly in theinfrared (IR) wavelengths. Otherwise, if the cleaning wafer istranslucent, IR wafer sensors in the prober machine read through thetranslucent characteristics of the cleaning wafer and the cleaning waferis now loaded. The cleaning wafer can be rendered opaque such as bybeing painted a dark color, or can be made opaque originally. Forexample, a high temperature brown or black paint can be sprayed on thebackside of a ceramic wafer disc. This prevents IR wafer sensors fromreading through the ceramic wafer disc, and enables the ceramic waferdisc to be loaded as if it were a silicon production wafer.

As discussed in more detail below, the cleaning wafer of the inventionhas a notch in an outer periphery thereof which allows for properalignment of the cleaning wafer when loaded into a prober machine. Forexample, a ⅛″{fraction (1/16)}″ notch can be cut in an outer peripheryof a ceramic wafer disc. The notch is used as a reference to establishcoordinates at 0°, 90°, 180°, and 270° around the wafer disc duringalignment of the wafer disc. This allows for orientating the wafer discand determining that the wafer disc has been centered and properlyaligned.

Referring to FIG. 1, a schematic overhead view of a prober machine orsystem 10 is depicted, which can use the cleaning wafer according to theinvention to clean probe pins on a probe card. The prober system 10 isbasically an automated wafer handler that is used to interface asemiconductor wafer with a testing device by using the probe pins on theprobe card for the electrical connections. The prober system 10 is runby software designed to accommodate a special cleaning cycle using thecleaning wafer of the invention to remove oxides and other debris fromthe probe pins.

The prober system 10 includes a load station 12 having a manual loadingtray with a drawer that pulls out, allowing a cleaning wafer disc 30 tobe placed thereon and inserted into prober system 10. The wafer disc 30may also be placed on an auxiliary tray located under an indexer 13. Theindexer 13 is used for cassette loading of wafer disc 30 automatically.A prealign stage 14 in prober system 10 includes a charge-coupled device(CCD) camera array 16, with optical character recognition (OCR). Anoptical sensor in camera array 16 detects a notch in cleaning wafer disc30 to properly align cleaning wafer disc 30 automatically. The cleaningwafer disc 30 is profiled at load position 20 by a profiler device (notshown), discussed in further detail below, to determine the thicknessand planarity of cleaning wafer disc 30. The prober system 10 alsoincludes a robotic trolley 18 having a robotic arm that is adapted totransport cleaning wafer disc 30 to the various stages of prober system10. For example, robotic trolley 18 is utilized to move cleaning waferdisc 30 from the loading tray to prealign stage 14, and from prealignstage 14 to a load position 20. The prober system 10 also includes aprobe station 22.

As shown in FIGS. 2 and 3, a means for supporting cleaning wafer disc 30in the form of a support device 32 is provided in prober system 10. Thesupport device 32 can be a vacuum chuck used to hold cleaning wafer disc30 in position under a probe card 24 with probe pins 26 at probe station22. The cleaning wafer disc 30 is held such that an abrasive surface 42of wafer disc 30 faces probe pins 26 to be cleaned. The support device32 has a top portion 34 such as a chuck top which supports cleaningwafer disc 30, and a z-stage section 36, which is interposed between topportion 34 and a forcer section 38 that floats pneumatically against aplaten 40. The forcer section 38 moves z-stage section 36 and has theability to compensate for any unevenness of cleaning wafer disc 30 andvariations in surface height of cleaning wafer disc 30.

When wafer disc 30 is placed on the chuck top of support device 32, thecenter of wafer disc 30 should align exactly with the center of thechuck top. Due to various reasons, however, this alignment does notalways occur and the profiler device is employed to perform thealignment. The profiler device hardware includes an electronics controlmodule (ECM) and a pneumatic sensor. The profiler device measures thewafer disc diameter and finds the center of the wafer disc in relationto the center of the chuck top. The profiler device then sends the exactwafer location information to support device 32 so that properadjustments are made. The profiler device uses backside spindle contactto measure the profile, thickness, and diameter of the wafer disc toautomatically find the wafer center and wafer edge. The measurements aretaken at either 1, 3, 5, or 9 points on the wafer.

The sensor of the profiler device may be lowered into operating positionor raised into a ring carrier under program control. The sensor emits astream of air which is used to detect back pressure, that is, how muchair is being reflected or bounced back into the sensor from a surface.This detected back pressure is used to determine the thickness of thewafer disc under the sensor. The detected back pressure is compared bythe electronics to a preset reference. The output of this comparatorfunction can be one of three states: sensor less than a reference,sensor equal to a reference, or sensor greater than a reference. Thecomparator output is sensed by the profiler software. For example, theECM can be set up so that the X19 equal condition occurs when the waferdisc (or chuck top) is 10 mils below the sensor. This 10-mil distance isthe reference distance, which means the wafer disc is more than 10 milsfrom the sensor, exactly 10 mils from the sensor, or less than 10 milsfrom the sensor. T.) measure wafer thickness, z-stage section 36 israised up until the comparator switches from the “wafer more than 10mils from sensor” state into either the “exactly 10 mils from sensor”state or the “less than 10 mils from sensor” state.

FIG. 3 shows an enlarged side view of probe card 24 with probe pins 26thereon which are positioned to be contacted with abrasive surface 42 ofcleaning wafer disc 30 supported on top portion 34. The probe card 24can have about 600 to 800 or more pins on a printed circuit board forprobe card 24. The probe pins 26 are preferably at about an angleorientation from a horizontal plane.

FIG. 4A shows more detail of cleaning wafer disc 30 with abrasivesurface 42 which can be used in prober system 10 to clean probe pins 26on probe card 24. The cleaning wafer disc 30 has a notch 31 along theouter periphery thereof to provide for proper alignment of wafer disc 30at prealign stage 14 in prober system 10.

FIG. 4B depicts another embodiment of the cleaning wafer of theinvention in the form of a cleaning wafer disc 50, which can also beutilized in prober system 10 to clean probe pins 26 on probe card 24.The cleaning wafer disc 50 has a notch 51 along the outer peripherythereof to provide for proper alignment of wafer disc 50 in probersystem 10. The cleaning wafer disc 50 has two distinct sections on thesurface thereof that will face the probe pins 26, including an abrasivesection 52 which can be made of a ceramic material, and a conductivesection 54 made of an electrically conductive material such as a metal.As discussed in more detail below, conductive section 54 allows probepins 26 to be tested during the cleaning cycle without having to removecleaning wafer disc 50 from prober system 10.

In operating prober system 10 of FIG. 1 in order to run a cleaning cyclefor probe pins 26 on probe card 24, the various components of probersystem 10 utilized during testing of silicon production wafers are alsoemployed to align and load the cleaning wafer. Thus, cleaning wafer disc30 is placed in the manual loading tray at load station 12 as indicatedby arrow A to begin a cleaning cycle for prober system 10.Alternatively, the wafer disc 30 can be placed in an auxiliary tray fromindexer 13. The robotic trolley 18 picks up cleaning wafer disc 30 asindicated by arrow B, and moves cleaning wafer disc 30 to prealign stage14 as indicated by arrow C, where cleaning wafer disc 30 is spun tolocate the notch thereon. The robot arm on robotic trolley 18 picks upcleaning wafer disc 30 and slides wafer disc 30 over to where it isperfectly centered on prealign stage 14, and wafer disc 30 is reorientedto have a start position of from 0° to 360° (e.g, 0°, 90°, 180°, 270°)from the notch thereon. The robot arm then moves wafer disc 30 to loadposition 20 as indicated by arrow D and onto top portion 34 of supportdevice 32, which in turn is moved to probe station 22 as indicated byarrow E so that wafer disc 30 is underneath probe card 24. The verticalor “z” height of support device 32 is then adjusted up and down asneeded to perform the cleaning operation. The cleaning wafer disc 30 iskept stationary beneath probe card 24 during the cleaning cycle as probepins 26 are touched down on wafer disc 30. The probe pins 26 can berepeatedly contacted with cleaning wafer disc 30 as needed to removeunwanted debris from probe pins 26. The cleaning wafer disc 30 isremoved from support device 32 and from the probe; machine when cleaningof probe pins 26 has been completed.

When the probe pins are contacted with the cleaning wafer of theinvention, a certain amount of over-travel or flexing of the pinsoccurs. For example, after initial contact of the probe pins on thesurface of the cleaning wafer, the z height of the cleaning wafer can befurther increased so that the pins have about a 3 to 5 mil over-travel.There are two options for moving the probe pins to produce a desiredover-travel. The first option is simply to move the probe pins up anddown, which will bend the probe pin tips up and down. The second optionis to utilize a jog mode in which the probe pins come down on thecleaning wafer, press down, and then move up. In the jog mode, the probepins are moved in the x direction, the y direction, and then an x-ydirection so that the probe pins are being moved in a generallyoctagonal pattern in three-dimensions while contenting the cleaningwafer. This allows the probe pin tips to be cleaned all over.

The prober system 10 is configured to automatically load the cleaningwafer to begin a cleaning cycle, perform some touch downs of the probepin tips on the cleaning wafer to remove debris from the probe pin tips,unload the cleaning wafer, and resume testing of production wafers.Accordingly, a prober control is employed capable of running an externalroutine that will control prober system 10 so that the necessarycommands required to perform the cleaning cycle are executed. Forexample, a portable computer can be operatively connected to probersystem 10 to run a generic communications program. Such a program caninstruct prober system 10 to profile a loaded clean ng wafer todetermine the thickness and planarity of the cleaning wafer so that anyvariations can be compensated for by z-stage section 36 on supportdevice 32. The program can also instruct prober system 10 to move thecleaning wafer to a specific x-y location that centers the chuck/waferunder the center of probe card 24, and then z-up to the currentz-work-height plus the entered z over-travel value. The program can thentell prober system 10 to unload the cleaning wafer to the manual loadingtray or the auxiliary tray.

The prober system 10 can be configured to load the cleaning wafer aftera set number of probe pin touch downs on a production wafer, or theprobe pins can be randomly tested to see whether or not a cleaning cycleis needed. Testing criteria can be built into production test programsso that the resistivity of the probe pins is checked to determine ifcleaning is required. For example, resistance in the probe pins cai bemeasured such that if resistivity increases by more than 4 ohms in theprobe pins, an error signal is triggered and a cleaning cycle iscommenced.

Alternatively, correlation failure tests can be run to check the probepins for debris build-up. For example, a whole production wafer can berun on one system and then the production wafer can be run on anothersystem. A map overlay is then done to see bin failure swapping. If onesite on the tested probe card varies from any of the other sites by morethan a standard deviation, a site difference signal is triggered andproduction will stop. The cleaning wafer of the invention can then beused to clean the probe pins before production is continued.

The probe pins on the probe card can be electrically tested during thecleaning operation to determine if the probe pins have been sufficientlycleaned, such as by gauging the resistance of the probe pins. Forexample, a production wafer can be shuttled back and forth to the probecard or a production wafer can be placed near the probe card to providea ground for the probe pins so that the pins can be electrically testedto determine whether the cleaning job is sufficient. A continuous cyclebetween the production wafer and the cleaning wafer can be run untilelectrical testing proves that the probe pins have been sufficientlycleaned, and then regular production and testing of silicon wafers canbe resumed.

In addition, as discussed above, the cleaning wafer can include aconductive section on a surface thereof, allowing the probe pins to betested during the cleaning cycle without having to remove the cleaningwafer away from the probe card. The conductive section can be used as anelectrical ground site for testing the probe pins to determine if thecleaning has been sufficient. For example, the probe pins can bealternately cleaned and tested during the cleaning cycle until it isdetermined that the cleaning is satisfactory through variousdiagnostics. Once the probe pins have been sufficiently cleaned,production can be resumed by shuttling a production wafer into theprober machine.

Further, after a predetermined period of use, the cleaning wafer itselfcan be cleaned of the oxides and other materials that have been scrapedoff the probe pins, allowing the cleaning wafer to be repeatedly reused.In another option, the life of the cleaning wafer or time betweencleanings of the wafer can be extended by simply using a different notchoffset for wafer orientation. The CCD in the prealign stage can beinstructed, through software, to look for the notch and rotate thecleaning wafer to a different position so the same cleaning wafer isused for another set of cleaning cycles. For example, there can be onesetting at 0, which can be used for 100 cleaning cycles, another settingat 90°, which can be used to enable another 100 cleaning cycles, adifferent setting at 180°, which can be used for another 100 cleaningcycles, and another setting at 270°, which can be used to enable another100 cleaning cycles. The different settings allow each set of 100cleaning cycles to be performed at different locations on the cleaningwafer, thereby extending the life of the cleaning wafer.

In another embodiment, a plurality of metal traces such as gold tracescan be placed on the cleaning wafer. The metal traces can be placed onthe cleaning wafer by a conventional deposition process such as chemicalvapor deposition. The metal traces can serve as ground sites forelectrically testing the probe pins during a cleaning cycle, and canalso be used to provide a first-to-last contact planarity range for theprobe pins. Since the probe pins on a probe card are at various heights,by touching the pins down on the metal traces, it can be determinedincrementally at what point individual probe pins contact the surface ofthe cleaning wafer.

The cleaning wafer embodiments of the invention can thus be used incleaning probe pin tips and to test whether the probe pin tips aresufficiently clean, and can be used in determining the planarity of theprobe pins.

The cleaning wafer of the invention allows wider probe cards to beeffectively cleaned while still loaded on a production prober machine.This allows the probe pins to be in service longer without having toremove the probe card for cleaning, reinstall a clean probe card, andrerun a complete new set-up for the clean probe card. Thus, theinvention results in a decrease in production downtime that isassociated with the removal of a known good probe card that just needsthe probe pin tips scrubbed or cleaned.

The present invention may be embodied in other specific forms withoutdeparting from its spirit or essential characteristics. The describedembodiments are to be considered in all respects only as illustrativeand not restrictive. The scope of the invention is, therefore, indicatedby the appended claims rather than by the foregoing description. Allchanges which come within the meaning and range of equivalency of theclaims are to be embraced within their scope.

What is claimed and desired to be secured by United States LettersPatent is:
 1. A wafer for cleaning a semiconductor device probe, thewafer comprising: a first p surface including a ceramic materialremoving unwanted debris from a probe tip; a second surface opposingsaid first surface the second surface having an opaque coating thereoncapable of blocking transmission of infrared light energy through thewafer; and an outer periphery between the first and second surfaces, theouter periphery having a notch formed therein for orienting the wafer ina stationary position during said removing unwanted debris.
 2. The waferof claim 1, wherein the ceramic material is selected from the groupconsisting of alumina, silicon nitride, silicon carbide, and mixturesthereof.
 3. The wafer of claim 1, wherein the wafer has a substantiallycircular shape.
 4. The wafer of claim 1, wherein the wafer has athickness in a range from about is 20 mil to about 40 mil.
 5. The waferof claim 1, wherein a portion of the first surface of the wafer is madeof an electrically conductive material.
 6. The wafer of claim 1, whereinthe first surface has metal traces deposited thereon.
 7. A wafer forcleaning a semiconductor device probe, the wafer comprising: a planarsubstrate with an outer periphery said substrate having a notch formedin said outer periphery for orienting the wafer; an abrasive material onthe substrate for removing unwanted debris from said semiconductordevice probe; and an opaque material on the substrate capable ofblocking transmission of nonionizing electromagnetic radiation energythrough the substrate.
 8. The system of claim 7, wherein at least aportion of the substrate is composed of a ceramic material.
 9. Thesystem of claim 8, wherein the ceramic material is selected from thegroup consisting of alumina, silicon nitride, silicon carbide, andmixtures thereof.
 10. The system of claim 7, wherein said nonionizingelectromagnetic radiation energy is infrared light.
 11. The system ofclaim 7, wherein the substrate has a thickness in a range from about 20mil to about 40 mil.
 12. The system of claim 7, wherein the substratehas a substantially circular shape.
 13. The system of claim 7, whereinthe substrate has a thickness in a range from about 10 mil to about 50mil.
 14. The system of claim 7, wherein a portion of the substrate ismade of an electrically conductive material.
 15. The system of claim 7,wherein the substrate has metal traces deposited on a surface thereof.16. The system of claim 15, wherein the metal traces are gold traces.17. A wafer for cleaning a semiconductor device probe, the wafer a firstsurface including a material for removing unwanted debris fromsemiconductor device probe, said material being selected from the groupconsisting of alumina, silicon nitride, silicon carbide, and mixturesthereof, a second surface opposing said first surface the second surfacehaving a coating thereon for blocking transmission therethrough ofinfrared light energy, and a circular outer periphery between the firstand second surfaces, the outer periphery having a notch formed thereinfor orienting the wafer in a stationary position during said removingunwanted debris.
 18. The wafer of claim 17, wherein the wafer has athickness in a range from about 20 mil to about 40 mil.
 19. The wafer ofclaim 17, wherein a portion of the first surface of the wafer is made ofan electrically conductive material.
 20. The wafer of claim 17, whereinthe first surface has metal traces deposited thereon.